The invention relates generally to physiological measurement systems, and more particularly, to a system and method for measuring pain in a patient.
Pain can be described as an unpleasant physical sensation experienced in response to injury, disease, or other negative stimuli. Although the experience of pain is extremely subjective, there is clearly a sensuous difference in pain felt by different people in different circumstances. Pain is an individual's subjective perception of an uncomfortable response to harmful stimulus to the body. Even when the diagnoses of the causes of the pain are identical, the perception of pain among different subjects can be quite different in terms of intensity and type of feeling. Pain is, therefore, an individual and subjective phenomena. For this reason, the quantification of the level of pain being experienced by an individual has been quite difficult.
However, it can definitely be said that pain can manifest at varying levels of distinguishable intensity that are related to the type and severity of the harmful stimuli. The perception of pain is, however, an individual response that is related to the individual subject's nervous system.
Furthermore, the perception of pain also has a psychological component that can cause different subjects to report their pain in different ways. For example, factors such as the individual subject's willpower (or lack thereof) and determination to overcome their illness or injury can influence the way in which they perceive and report their pain.
Some people have what is referred to as a high pain tolerance and others a low pain tolerance. That is, higher levels of pain may be experienced by those individuals possessing a high pain tolerance before they are unable to function in a normal manner or are otherwise adversely affected. For those persons having a low tolerance for pain, lower levels of pain adversely affect them. Thus, the pain may be somewhat subjective or at least is relative to each patient.
Determining how much pain is experienced by a particular patient can be helpful in treating that patient. In one situation, a patient may be the subject of a therapy program to overcome an injury or disease. Determining how much pain a patient experiences during the course of the therapy may greatly aid the therapist in selecting the proper therapies to provide to the patient. For example, a patient who is recovering from a shoulder injury may be experiencing a certain level of pain at the beginning of a therapy program. As the therapy proceeds, it would be helpful to the therapist to know if the pain is decreasing thereby indicating that the therapy is successful or at least is not aggravating the injury. However, if the level of pain does not decrease over time, or if it increases, knowledge of this could also aid the therapist in selecting other programs for the patient or in referring the patient back to a physician for further diagnosis.
In another situation, a patient may experience "soft tissue" injury. That is, no physical damage to the patient's body is apparent either visibly, by x-ray, or by other means yet the patient complains of pain. A therapy program may also be prescribed for this patient. Unfortunately, the program would be based upon the patient's expression of the level and location of his pain. It would be beneficial to have an objective measure for such a patient's pain level so the effects of any therapy program could be more accurately determined.
Therapies may be prescribed for such patients and are based only on the patient's input as to where the pain is in his body and under what conditions it worsens or lessens. In this case, there are no independent means to diagnosis the progress of the therapy other than the patient's subjective opinion that the pain is decreasing or increasing. It would be helpful to the therapist and physician to have a more objective indication of the level of pain experienced by the patient.
In a related circumstance to "soft tissue" and other pain, it has been found that in some cases a patient may complain of extreme pain when little or none is actually experienced. The reasons for doing so vary and may include pecuniary gain or an attempt to avoid further work. It would be helpful to be able to more objectively and more accurately test such a patient for the actual existence of pain.
Hence those skilled in the art have recognized the need for an improved pain measurement system and method capable of more accurately quantifying the amount of pain experienced by a patient. A further need has been recognized for a system and method that are able to more accurately determine if pain actually exists in a patient. The present invention fulfills these needs and others.